Fix constrained snap when dragging by a compass rose axis and fix that axis line's jiggling (#2333)

* Fixes constrained snap when using compass axes; Fix line banding

Fixes #2313
Fixes line banding[0]

[0]: https://discord.com/channels/731730685944922173/931942323644928040/1345339390809083934

* Separate axis align and axis constraint logic

* Final fix

* Use projection instead of length

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

Author: mTvare6

editor/src/messages/tool/common_functionality/compass_rose.rs

@@ -101,3 +101,13 @@ impl Axis {
 		matches!(self, Self::X | Self::Y)
 	}
 }
+
+impl From<Axis> for DVec2 {
+	fn from(value: Axis) -> Self {
+		match value {
+			Axis::X => DVec2::X,
+			Axis::Y => DVec2::Y,
+			Axis::None => DVec2::ZERO,
+		}
+	}
+}

editor/src/messages/tool/common_functionality/transformation_cage.rs

@@ -8,6 +8,7 @@ use crate::messages::frontend::utility_types::MouseCursorIcon;
 use crate::messages::portfolio::document::overlays::utility_types::OverlayContext;
 use crate::messages::portfolio::document::utility_types::transformation::OriginalTransforms;
 use crate::messages::prelude::*;
+use crate::messages::tool::common_functionality::compass_rose::Axis;
 use crate::messages::tool::common_functionality::snapping::SnapTypeConfiguration;
 use glam::{DAffine2, DMat2, DVec2};
 use graphene_core::renderer::Quad;
@@ -286,25 +287,30 @@ impl SelectedEdges {
 }
 
 /// Aligns the mouse position to the closest axis
-pub fn axis_align_drag(axis_align: bool, position: DVec2, start: DVec2) -> DVec2 {
+pub fn axis_align_drag(axis_align: bool, axis: Axis, position: DVec2, start: DVec2) -> DVec2 {
 	if axis_align {
 		let mouse_position = position - start;
 		let snap_resolution = SELECTION_DRAG_ANGLE.to_radians();
 		let angle = -mouse_position.angle_to(DVec2::X);
 		let snapped_angle = (angle / snap_resolution).round() * snap_resolution;
+		let axis_vector = DVec2::from_angle(snapped_angle);
 		if snapped_angle.is_finite() {
-			start + DVec2::new(snapped_angle.cos(), snapped_angle.sin()) * mouse_position.length()
+			start + axis_vector * mouse_position.dot(axis_vector).abs()
 		} else {
 			start
 		}
+	} else if axis.is_constraint() {
+		let mouse_position = position - start;
+		let axis_vector: DVec2 = axis.into();
+		start + axis_vector * mouse_position.dot(axis_vector)
 	} else {
 		position
 	}
 }
 
 /// Snaps a dragging event from the artboard or select tool
-pub fn snap_drag(start: DVec2, current: DVec2, axis_align: bool, snap_data: SnapData, snap_manager: &mut SnapManager, candidates: &[SnapCandidatePoint]) -> DVec2 {
-	let mouse_position = axis_align_drag(axis_align, snap_data.input.mouse.position, start);
+pub fn snap_drag(start: DVec2, current: DVec2, snap_to_axis: bool, axis: Axis, snap_data: SnapData, snap_manager: &mut SnapManager, candidates: &[SnapCandidatePoint]) -> DVec2 {
+	let mouse_position = axis_align_drag(snap_to_axis, axis, snap_data.input.mouse.position, start);
 	let document = snap_data.document;
 	let total_mouse_delta_document = document.metadata().document_to_viewport.inverse().transform_vector2(mouse_position - start);
 	let mouse_delta_document = document.metadata().document_to_viewport.inverse().transform_vector2(mouse_position - current);
@@ -324,7 +330,8 @@ pub fn snap_drag(start: DVec2, current: DVec2, axis_align: bool, snap_data: Snap
 		let mut point = point.clone();
 		point.document_point += total_mouse_delta_document;
 
-		let snapped = if axis_align {
+		let constrained_along_axis = snap_to_axis || axis.is_constraint();
+		let snapped = if constrained_along_axis {
 			let constraint = SnapConstraint::Line {
 				origin: point.document_point,
 				direction: total_mouse_delta_document.try_normalize().unwrap_or(DVec2::X),

editor/src/messages/tool/tool_messages/artboard_tool.rs

@@ -3,6 +3,7 @@ use crate::messages::portfolio::document::graph_operation::utility_types::Transf
 use crate::messages::portfolio::document::overlays::utility_types::OverlayContext;
 use crate::messages::portfolio::document::utility_types::document_metadata::LayerNodeIdentifier;
 use crate::messages::tool::common_functionality::auto_panning::AutoPanning;
+use crate::messages::tool::common_functionality::compass_rose::Axis;
 use crate::messages::tool::common_functionality::resize::Resize;
 use crate::messages::tool::common_functionality::snapping;
 use crate::messages::tool::common_functionality::snapping::SnapCandidatePoint;
@@ -283,7 +284,7 @@ impl Fsm for ArtboardToolFsmState {
 					let snap_data = SnapData::ignore(document, input, &ignore);
 					let document_to_viewport = document.metadata().document_to_viewport;
 					let [start, current] = [tool_data.drag_start, tool_data.drag_current].map(|point| document_to_viewport.transform_point2(point));
-					let mouse_delta = snap_drag(start, current, axis_align, snap_data, &mut tool_data.snap_manager, &tool_data.snap_candidates);
+					let mouse_delta = snap_drag(start, current, axis_align, Axis::None, snap_data, &mut tool_data.snap_manager, &tool_data.snap_candidates);
 
 					let size = bounds.bounds[1] - bounds.bounds[0];
 					let position = bounds.bounds[0] + bounds.transform.inverse().transform_vector2(mouse_delta);

editor/src/messages/tool/tool_messages/select_tool.rs

@@ -319,6 +319,7 @@ struct SelectToolData {
 	cursor: MouseCursorIcon,
 	pivot: Pivot,
 	compass_rose: CompassRose,
+	line_center: DVec2,
 	skew_edge: EdgeBool,
 	nested_selection_behavior: NestedSelectionBehavior,
 	selected_layers_count: usize,
@@ -660,6 +661,9 @@ impl Fsm for SelectToolFsmState {
 				// Update compass rose
 				tool_data.compass_rose.refresh_position(document);
 				let compass_center = tool_data.compass_rose.compass_rose_position();
+				if !matches!(self, Self::Dragging { .. }) {
+					tool_data.line_center = compass_center;
+				}
 				overlay_context.compass_rose(compass_center, angle, show_compass_with_ring);
 
 				let axis_state = if let SelectToolFsmState::Dragging { axis, .. } = self {
@@ -691,7 +695,8 @@ impl Fsm for SelectToolFsmState {
 								let color_string = &graphene_std::Color::from_rgb_str(color.strip_prefix('#').unwrap()).unwrap().with_alpha(0.25).rgba_hex();
 								&format!("#{}", color_string)
 							};
-							overlay_context.line(compass_center - direction * viewport_diagonal, compass_center + direction * viewport_diagonal, Some(color));
+							let line_center = tool_data.line_center;
+							overlay_context.line(line_center - direction * viewport_diagonal, line_center + direction * viewport_diagonal, Some(color));
 						}
 					}
 				}
@@ -984,20 +989,21 @@ impl Fsm for SelectToolFsmState {
 					tool_data.stop_duplicates(document, responses);
 				}
 
-				tool_data.axis_align = input.keyboard.key(modifier_keys.axis_align) && !axis.is_constraint();
+				tool_data.axis_align = input.keyboard.key(modifier_keys.axis_align);
 
 				// Ignore the non duplicated layers if the current layers have not spawned yet.
 				let layers_exist = tool_data.layers_dragging.iter().all(|&layer| document.metadata().click_targets(layer).is_some());
 				let ignore = tool_data.non_duplicated_layers.as_ref().filter(|_| !layers_exist).unwrap_or(&tool_data.layers_dragging);
 
 				let snap_data = SnapData::ignore(document, input, ignore);
 				let (start, current) = (tool_data.drag_start, tool_data.drag_current);
-				let mouse_delta = snap_drag(start, current, tool_data.axis_align, snap_data, &mut tool_data.snap_manager, &tool_data.snap_candidates);
 				let e0 = tool_data
 					.bounding_box_manager
 					.as_ref()
 					.map(|bounding_box_manager| bounding_box_manager.transform * Quad::from_box(bounding_box_manager.bounds))
 					.map_or(DVec2::X, |quad| (quad.top_left() - quad.top_right()).normalize_or(DVec2::X));
+
+				let mouse_delta = snap_drag(start, current, tool_data.axis_align, axis, snap_data, &mut tool_data.snap_manager, &tool_data.snap_candidates);
 				let mouse_delta = match axis {
 					Axis::X => mouse_delta.project_onto(e0),
 					Axis::Y => mouse_delta.project_onto(e0.perp()),